I have never quite been a master of the d3d9 blend modes.. I know the basic stuff, but have been trying for a while to get a multiply/add blending mode... the best I can figure out is mult2x by setting:

SetRenderState(D3DRS_DESTBLEND, D3DBLEND_SRCCOLOR);
SetRenderState(D3DRS_SRCBLEND, D3DBLEND_DESTCOLOR);

//this isn't quite what I want.. basically I wonder if there is a way to like multiply by any color darker than 0.5 and add by any color lighter than that..? I don't know, maybe this system is too limited...